I wanted to ask are there any disadvantages of signing up for the developer program? I cant wait any longer..

The disadvantage is that the software is not optimized for your device (hardware). It will not get you the next level of firmware... Black to Cyan or Cyan to Denim - only an official OTA update wil bring the firmware advance. Some common symptoms include shortened battery life and connectivity problems especially with WiFi... That said, overall response to the Preview for Developers program has been very positive. I would urge you first to check the forum for your particular device and see what users of P4D on your model have to say.